Undefined index in Array

Question

I have my grid-array in my flash game that has a set sized index in it, and through some code it sometimes checks outside of the Array index. Is there a way I can check to see if a index slot is undefined/existent

Gives me a TypeError #1010

public function fnPopulate(X:int, Y:int, Grid:Array){
    if (Grid[ X + 1 ][ Y + 1 ] != null || Grid[ X + 1 ][ Y + 1 ] != undefined ) {
    return(true);
    } 

    return(false);
}

Any advise is appreciated, Thank you in advance.

P.S. Is there a reason why it keeps deleting my greeting?

liupeixin · Accepted Answer · 2012-03-29 03:57:47Z

1

you need to check the first dimensional of array.
and obj!= null, obj!= undefined means if(obj){....}

public function fnPopulate(X:int, Y:int, Grid:Array)
{
    if (Grid[ X + 1 ] && Grid[ X + 1 ][ Y + 1 ]) 
    {
        return(true);
    } 

    return(false);
}

answered Mar 29, 2012 at 3:57

liupeixin

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Comments

wharfie · Accepted Answer · 2012-03-29 03:01:59Z

1

How about

if ( (X<Grid.length) && (Y<Grid[X].length) ) return(true) else return(false);

answered Mar 29, 2012 at 3:01

wharfie

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3 Comments

L.P. Over a year ago

If true is returned it then attempts to places a object in that Index slot. So I kind of need to check if it is there or not.

L.P. Over a year ago

Tried adding your suggestion in this way at the start of the function: if (X+1 >= 10 || +1 >= 9) {return(true);} Still errors later on in the code because sometimes I still will address non-existing index.

Creynders Over a year ago

you could simplify this even more: return (X<Grid.length) && (Y<Grid[X].length);

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